Plaque Vascularization Research Articles

Myeloid GSK3α Deficiency Reduces Lesional Inflammation and Neovascularization during Atherosclerotic Progression.

The molecular mechanisms by which cardiovascular risk factors promote the development of atherosclerosis are poorly understood. We have recently shown that genetic ablation of myeloid glycogen synthase kinase (GSK)-3α attenuates atherosclerotic lesion development in low-density lipoprotein receptor-deficient (Ldlr-/-) mice. However, the precise contributions of GSK3α/β in atherogenesis are not known. The aim of this study is to investigate the effect of GSK3α and/or β deficiency on lesional inflammation and plaque vascularization. Five-week-old female Ldlr-/- mice were fed a high-fat diet for 10 weeks to establish atherosclerotic lesions. Mice were harvested at 15 weeks of age and atherosclerotic lesions were characterized. The results indicate that, in addition to significantly reducing plaque volume, GSK3α-deficiency decreases inflammation, reduces vasa vasorum density at the aortic sinus, and reduces plasma c-reactive protein (CRP) levels. GSK3β-deficiency is associated with decreased plasma CRP levels but does not affect lesional inflammation or vascularization. These results suggest GSK3α may be an applicable target for the development of novel anti-atherogenic therapies.

Assessment of Plaque Characteristics by Contrast-Enhanced Ultrasound and Stent Restenosis following Carotid Artery Stenting: A Retrospective Study

Background and objective: carotid artery stenosis contributes significantly to ischemic strokes, with management options including carotid endarterectomy (CEA) and carotid artery stenting (CAS) ischemic stroke risk can be reduced. Controversies persist regarding their efficacy and factors influencing complications, and understanding the relationship between atherosclerotic plaque characteristics and stent restenosis after CAS is crucial. Methods: we conducted a retrospective study involving 221 patients who underwent CAS for symptomatic or asymptomatic carotid artery stenosis. Comprehensive assessments of plaque morphology were performed using contrast-enhanced ultrasound (CEUS) before CAS. Patient demographics, including smoking status and diabetes, were also recorded. Stent restenosis was diagnosed using various imaging modalities, including ultrasound, angiography, and digital subtraction angiography (DSA). Results: plaque analysis using CEUS revealed a significant association between plaque grade and restenosis incidence (p < 0.001), particularly with grade 0 (11.1%) and grade 2 plaques (66.7%). Smoking was notably associated with plaque vascularization and restenosis (p < 0.001), while diabetes did not significantly impact plaque characteristics or restenosis risk (p > 0.05). The mean duration of restenosis was 17.67 months. Stenting was the most frequent treatment modality for restenosis (70.6%). However, no significant relationship was found between restenosis type and plaque morphology (p = 0.268). Furthermore, while no clear relationship was observed between plaque morphology and the type of restenosis, our findings underscored the importance of plaque characterization in predicting post-CAS outcomes. Conclusions: this study highlights the utility of CEUS in predicting stent restenosis following CAS. There was a significant association between stent restenosis within 12–24 months after the carotid stenting procedure and an elevated grade of plaque vascularization. Moreover, one of the main factors possibly determining the grade of plaque vascularization was smoking. Further research is warranted to elucidate the underlying mechanisms and refine risk stratification in this patient population.

Regularities of plaque stabilization in various scenarios of neointimal calcification and vascularization

Aim. To study the relationships between phenotypes of extracranial arteries' plaques (stable/unstable), their calcification and its causes, in particular, vascularization.Material and methods. The study included 88 patients: patients (n=44) with ischemic stroke and those (n=44) with chronic brain ischemia. In all subjects, the parameters of systemic mineral homeostasis were assessed (total and ionized calcium, phosphate, total protein, albumin, and calcification propensity). Atherosclerotic plaques have been obtained during carotid endarterectomy, fixed in formalin, postfixed in 1% osmium tetroxide, stained in 2% osmium tetroxide, dehydrated in ascending ethanol series and acetone, stained with 2% alcoholic uranyl acetate and embedded into epoxy resin with its further polymerization. Epoxy resin blocks were grinded, polished, counterstained with Reynolds' lead citrate and sputter coated with carbon. Sample visualization was performed employing backscattered scanning electron microscopy. Number and area of calcium deposits and neointimal vessels were quantified using ImageJ. Statistical analysis was carried out using Mann-Whitney U-test and Spearman's rank correlation coefficient.Results. It was found that area of neointimal calcification, but not number of calcium deposits, was associated with the stable plaque phenotype. The stabilizing effect of calcification was manifested in retarding stenosis associated with plaque rupture and stroke. Calcification extent directly correlated with total and local plaque vascularization, which have been associated with unstable and stable plaque phenotype, respectively. In addition, plaque calcification negatively correlated with total protein and albumin, thereby reflecting the impaired systemic mineral homeostasis.Conclusion. Atherosclerotic plaque calcification and active local vascularization reduce stenosis extent and stabilize plaque. In contrast, total plaque calcification contributes to the atherosclerosis progression and promotes major acute cardiovascular events.

Radiofrequency Ablation of the Atherosclerotic Plaque: a Proof of Concept Study in an Atherosclerotic Model

Increased plaque vascularization is causatively associated with the progression of unstable atherosclerotic vessel disease. We investigated the safety and efficacy of heat-generating radiofrequency ablation (RFA) in reducing the number of vessels in the plaque and adventitia and its effect on plaque size and composition. To this end, New Zealand White rabbits were fed a cholesterol-enriched diet and subjected to balloon denudation of the infrarenal aorta to induce atherosclerotic plaque formation. After 13 weeks, the proximal or distal half of the infrarenal aorta was exposed to transluminal RFA. The untreated half served as an intra-individual control. Optical coherence tomography (OCT) was performed directly after RFA. We found that RFA on the rabbit atherosclerotic plaque is safe and leads to decreased intraplaque vessel density and smooth muscle cell content but does not affect other components of plaque composition or size.

Abstract 648: Alternative Macrophages Promote Atherosclerosis Progression by Increasing Intraplaque Angiogenesis and Vascular Permeability via HIF-1 alpha/VEGF-A-dependent Pathway

Background: Alternative macrophages exist in human atherosclerosis but their role in atherogenesis remains uncertain. Intraplaque hemorrhage (IPH) is an important stimulus driving alternative macrophage polarization. Intake of hemoglobin (Hb) by the hemoglobin: haptoglobin receptor CD163 leads to a distinct non-foam cell phenotype termed M(Hb). These cells demonstrate upregulation of CD163, lack of lipid retention, and anti-oxidative properties, characteristics considered ‘atheroprotective’. Here we reveal an unexpected but important pathogenic role for M(Hb) in atherosclerosis. Objectives: To determine the role of M(Hb) macrophages in human intraplaque angiogenesis and vascular permeability. Methods: Using human atherosclerotic samples, cultured cells, and a mouse model of IPH, we investigated the role of IPH on macrophage function with respect to angiogenesis and vascular permeability. Results: Within M(Hb) activation of hypoxia-inducible factor-1 alpha (HIF-1) via inhibition of prolyl hydroxylases promotes intraplaque angiogenesis and vascular permeability. In human carotid plaques, alternative CD163 positive macrophages were found to be highly associated with plaque vascularity and expressed high levels of HIF1- and vascular endothelial growth factor-A (VEGF-A). Supernatants from hemoglobin:haptoglobin differentiated M(Hb) macrophages increased endothelial permeability and led to internalization of the endothelial barrier protein vascular endothelial cadherin (VE-cadherin) via activation of VEGF receptor 2 (VEGFR2). Areas of plaque demonstrating high density CD163 high macrophage subsets showed irregular VE-cadherin immunostaining and diffuse perivascular collections of von Willebrand factor suggesting microvessel incompetence. Finally, in brachiocephalic plaques of one-year-old apoE -/- and apoE -/- CD163 -/- mice, CD163 deficiency significantly reduced plaque progression, lesion size, and intraplaque hemorrhage, but had little effect on lesions uncomplicated by hemorrhage. Conclusions: Our findings provide a novel non-lipid driven mechanism by which alterative M(Hb) macrophages promote plaque neoangiogenesis and microvessel incompetence via a HIF-1/VEGF-A-dependent pathway.

Summary of clinical and laboratory data of study subjects with and without DCE-MRI plaque measurements in the AIM-HIGH clinical trial.

This brief data article summarizes the clinical risk factors and laboratory data of a group of subjects recruited for the AIM-HIGH trial (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides and Impact on Global Health Outcomes) and an associated magnetic resonance imaging (MRI) substudy. The sample is restricted to those on statin therapy at the time of enrollment and data are presented stratified by whether dynamic contrast enhanced MRI (DCE-MRI) markers of carotid plaque vascularity and inflammation were available or not. The data provided herein are directly related to the article “Longer Duration of Statin Therapy is Associated with Decreased Carotid Plaque Vascularity by Magnetic Resonance Imaging” [2].

Longer duration of statin therapy is associated with decreased carotid plaque vascularity by magnetic resonance imaging

ObjectivePlaque neovasculature is a major route for lipoprotein and leukocyte ingress into plaques, and has been identified as a risk factor for carotid plaque disruption. Vp, a variable derived from pharmacokinetic modeling of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), correlates with plaque neovasculature density. Because lipid-lowering therapy has been associated with regression of neovasculature in animal models, we sought to determine clinical correlates of carotid plaque neovasculature (as assessed by Vp) in participants on statin therapy for established cardiovascular disease. Methods98 participants from an AIM-HIGH sub-study underwent DCE-MRI of their carotid arteries. Expert readers who were blinded to all clinical variables analyzed the MR images to measure carotid plaque Vp in all participants. Associations between Vp and duration of statin therapy and other clinical risk factors were analyzed. ResultsPrior duration of statin treatment at enrollment ranged from <1 year (21%) 1–5 years (40%) and >5 years (39%). In univariate analyses, shorter duration of statin therapy (P = 0.01), the presence of metabolic syndrome (P = 0.02), and higher body mass index (P = 0.01) and lipoprotein(a) (P = 0.01) were all significantly associated with higher baseline Vp values. In multivariate analyses, significant associations remained between shorter duration of statin therapy (P = 0.004) and lipoprotein(a) (P = 0.04). ConclusionsThese are the first human, in vivo findings suggesting a relationship between duration of statin therapy and regression of carotid plaque neovasculature. Future longitudinal studies are warranted both to confirm this finding and to address whether changes in neovasculature may translate into change in risk for plaque disruption. ClinicalTrials.gov IdentifiersNCT00880178, NCT01178320 and NCT00120289.

Neovascularization of the atherosclerotic plaque: interplay between atherosclerotic lesion, adventitia-derived microvessels and perivascular fat.

Neovascularization is a prominent feature in advanced human atherosclerotic plaques. This review surveys recent evidence for and remaining uncertainties regarding a role of neovascularization in atherosclerotic plaque progression. Specific emphasis is given to hypoxia, angiogenesis inhibition, and perivascular adipose tissue (PVAT). Immunohistochemical and imaging studies showed a strong association between hypoxia, inflammation and neovascularization, and the progression of the atherosclerotic plaque both in humans and mice. Whereas in humans, a profound invasion of microvessels from the adventitia into the plaque occurs, neovascularization in mice is found mainly (peri)adventitially. Influencing neovascularization in mice affected plaque progression, possibly by improving vessel perfusion, but supportive clinical data are not available. Whereas plaque neovascularization contributes to monocyte/macrophage accumulation in the plaque, lymphangiogenesis may facilitate egress of cells and waste products. A specific role for PVAT and its secreted factors is anticipated and wait further clinical evaluation. Hypoxia, inflammation, and plaque neovascularization are associated with plaque progression as underpinned by recent imaging data in humans. Recent studies provide new insights into modulation of adventitia-associated angiogenesis, PVAT, and plaque development in mice, but there is still a need for detailed information on modulating human plaque vascularization in patients.

Use of Contrast-Enhanced Ultrasound in Carotid Atherosclerotic Disease: Limits and Perspectives.

Contrast-enhanced ultrasound (CEUS) has recently become one of the most versatile and powerful diagnostic tools in vascular surgery. One of the most interesting fields of application of this technique is the study of the carotid atherosclerotic plaque vascularization and its correlation with neurological symptoms (transient ischemic attack, minor stroke, and major stroke) and with the characteristics of the “vulnerable plaque” (surface ulceration, hypoechoic plaques, intraplaque hemorrhage, thinner fibrous cap, and carotid plaque neovascularization at histopathological analysis of the sample after surgical removal). The purpose of this review is to collect all the original studies available in literature (24 studies with 1356 patients enrolled) and to discuss the state of the art, limits, and future perspectives of CEUS analysis. The results of this work confirm the reliability of this imaging study for the detection of plaques with high risk of embolization; however, a shared, user-friendly protocol of imaging analysis is not available yet. The definition of this operative protocol becomes mandatory in order to compare results from different centers and to validate a cerebrovascular risk stratification of the carotid atherosclerotic lesions evaluated with CEUS.

Abstract 17471: 3D Contrast-enhanced Ultrasound (CEUS) Imaging of Carotid Artery Plaques and Intra-plaque Angiogenesis

Introduction: Vulnerable plaque is marked by increased intra-plaque vascularity, hemorrhage and is associated with cerebrovascular (CV) events. Current use of 2D CEUS carotid imaging does not provide a true volumetric representation of the intra-plaque angiogenesis. Therefore, this is the first clinical trial using 3D CEUS to assess intra-plaque angiogenesis, in patients with clinically significant plaques prior to carotid endarterectomy (CEA). Methods: Data were acquired on 11 patients that were asked to participate in this pilot study prior to CEA. All patients had MR and/or CT angiogram as part of their standard care and all carotid artery plaque specimens were collected and sent for histologic evaluation. CEUS volumes were acquired using a GE LOGIQ E9, RSP6-16 4D probe and Optison. In order to assess plaque vulnerability, semi-automatic image analysis algorithms were developed to segment the lumen, plaque, and intra-plaque vascularity. Measurements derived from 3D CEUS images were validated against CT, MR, and histology. Results: Preliminary results from 3 patients were analyzed and lumen volumes were segmented from all available modalities (figure shows CEUS example). Lumen measurements of the CCA, ICA, and ECA from 3D CEUS were compared to MR or CT. High correlation is shown in the figure for these patients (R 2 =0.95). Further analysis of the 3D CEUS images demonstrates that we can identify intra-plaque vascularity (see segmentation from one patient). These CEUS results estimated an average cross-sectional vascular density of 7-11% in the plaque, matching histology estimates of 10% from a single slice. Conclusion: These results demonstrate that it is feasible to use 3D CEUS for quantitative, volumetric imaging of the carotid artery and intra-plaque angiogenesis in patients scheduled for CEA. Future work will extend this analysis to all patients and make a quantitative comparison of intra-plaque vascular density from 3D CEUS vs. multiple histology slices.

Imaging intracranial vessel wall pathology with magnetic resonance imaging: current prospects and future directions.

To date, the probable cause of ischemic stroke is often inferred from the size and location of the infarct, in combination with an evaluation of the heart and the presence of extracranial arterial occlusion or high-grade stenosis.1 Currently used conventional lumenography-based methods such as digital subtraction angiography, computed tomography angiography, and magnetic resonance (MR) angiography are used to determine the presence of such an acute occlusion or high-grade arterial stenosis. From extracranial studies, it is known that luminal narrowing may be absent in patients with severe atherosclerosis owing to arterial remodeling.2–4 Therefore, these methods do not provide information about the underlying pathological processes, which most often involve the vessel wall.5 Vessel wall changes such as vessel wall thickening, enhancement, or the presence of vulnerable atherosclerotic plaques without luminal stenosis are therefore often missed but might be of importance for a better understanding of ischemic stroke.6 Furthermore, intracranial atherosclerosis is an important cause of ischemic stroke7 and often involves the vessel wall. Patients with intracranial atherosclerosis have high recurrent stroke rates,8 and increasingly more attention is being directed to the assessment of the intracranial vessel wall, necessitating an imaging technique directly assessing the intracranial vessel wall. MR imaging (MRI) seems the most promising technique to reliably image intracranial vessel wall pathologies because of its superior soft tissue contrast. Recent advances in MRI9 have made it possible to obtain information about these abnormalities within the intracranial vessel wall, which provides an imaging tool to investigate the role of intracranial vessel wall abnormalities in the diagnosis of stroke. In this review, we discuss the current status of intracranial vessel wall MRI and its potential to identify different intracranial vessel wall pathologies. First, we present the state-of-the-art MRI methods to visualize the intracranial vessel wall …

A study of plaque vascularization and inflammation using quantitative contrast-enhanced US and PET/CT

BackgroundContrast-enhanced ultrasound (CEUS) is an in vivo methodology to quantify carotid plaque vascularization. Increased metabolism in plaques, measured as FDG uptake in PET/CT examination, has been associated with markers of inflammation in histological samples. In this study, we tested the association between FDG uptake and vascularization measured by CEUS to assess whether CEUS can be used as an in vivo marker of plaque vulnerability. MethodsAfter informed consent, subjects aged >60 years with carotid plaque height exceeding 2.5mm were recruited. CEUS was performed and analyzed using earlier described protocol and software, Contrast Quantification Program, which calculates the fraction of the plaque being contrast positive (CQP value). PET/CT examination was performed within 3 months of CEUS (median time 7 days). PET/CT images were acquired 90min after FDG injection (2.7MBq/kg). FDG uptake was measured as tissue background index (TBI), calculated using Spearman's rho as mean standard uptake value (SUV) of the plaque divided by mean SUV in the jugular vein (mean of 7 measuring points). Local ethics committee approved the study. ResultsWe recruited 13 subjects (5 women) with a mean age of 71 years, 6 had a history of stroke or TIA, 1 had a history of ipsilateral stroke. CQP values showed a significant, positive correlation with TBI of carotid plaques, r=0.67, p<0.02. ConclusionsPlaque vascularization measured by CEUS correlates positively with FDG uptake measured by PET/CT in humans. This indicates an association between vascularization and inflammation and/or hypoxia, supporting the use of CEUS as a non-invasive method to detect plaque vulnerability.

Dual-frequency intravascular ultrasound transducer design for contrast agent imaging

Intravascular ultrasound (IVUS) is a unique diagnostic tool for assessing the composition and degree of stenosis of atheromata in cardiovascular disease. As of yet, contrast enhanced IVUS has not been clinically implemented despite its potential to provide functional information, such as degree of plaque vascularization, in conjunction with standard anatomical mapping. In this study, we demonstrate that nonlinear microbubble signals can be detected with minimal signal processing using an ultra-broadband IVUS transducer composed of a low frequency transmit and a high frequency receive combined element. Raw signals were acquired from a single element transducer (1 × 3 mm, fc = 6.5/35 MHz) after aligning to an acoustically transparent 200 µm inner diameter cellulose tube. Poly-disperse, (1–10 µm diameter) lipid-coated microbubbles were injected at high concentration (4.8 × 108 MBs/mL) and peak negative pressures were varied from −0.3 to −1.8 MPa while transmission cycles were increased from 1to 5. In vitro results indicate signal to noise ratios of 11 dB are attainable at 2nd harmonics and similar SNRs (10–8 dB) at higher harmonics. The results of this study indicate that contrast enhanced IVUS imaging is possible using a single transmit pulsing scheme enabled by using a dual- frequency broadband transducer design.

Neovascular endothelial-cell activation: The link between angiogenesis, intimal leukocyte content, and development of symptomatic carotid occlusive disease

New blood vessels in atherosclerotic lesions are postulated to be responsible for plaque instability by acting as conduits for inflammatory cells. This study assessed the association between macrophage content of plaque caps of carotid atherosclerotic lesions, plaque vascularity, and endothelial-cell activation within these blood vessels. Carotid endarterectomy specimens from patients who underwent endarterectomy for carotid occlusive disease (ten symptomatic, six asymptomatic) were examined. Sequential transverse sections were obtained and were stained conventionally and immunohistochemically with CD 34 (an endothelial-cell marker) and CD 68 (a macrophage marker), as well as VCAM-1 and ICAM-1 (markers of endothelial-cell activation). Microvessel and macrophage counts were performed for the whole plaque and the plaque cap respectively. The differences in microvessel density, macrophage content, and ICAM-1 and VCAM-1 expression, between symptomatic and asymptomatic patients and in different plaque types were examined, as was the association between microvessel density and microvessel content of atherosclerotic lesions. Higher microvessel counts were observed in patients with symptomatic carotid occlusive disease (p < 0.01). Higher ICAM-1 and VCAM-1 expression was noted in new blood vessels in plaques obtained from patients with symptomatic carotid occlusive disease, compared with asymptomatic patients (p < 0.001 and p < 0.01 respectively). A close association was observed between macrophage content of the plaque cap and microvessel counts in atherosclerotic lesions (p < 0.0001), as well as ICAM-1 (p < 0.001) and VCAM-1 (p < 0.001) expression, in these microvessels. This study highlights the significance of neovascularity and endothelial-cell activation in the evolution of symptomatic carotid occlusive disease. Furthermore, it points to a relationship between the inflammatory process and angiogenesis within the plaque, which may be mediated through endothelial-cell activation.

Current Strategies and Possible Perspectives of Ultrasonic Risk Stratification of Ischemic Stroke in Internal Carotid Artery Disease

Atherosclerotic alterations of the internal carotid artery frequently result in ischemic stroke. However, it remains unclear which specific factor mainly causes an increased risk of stroke. Constant improvements of the diagnostic possibilities of ultrasonic examinations provide increasingly profound insight into plaque alterations. If "risk plaque" could be reliably identified, the therapeutic decision for either medical or surgical treatment could be made more rationally. In this review, we summarize current developments in the ultrasound imaging of atherosclerotic changes in carotid artery disease with special emphasis on technical aspects and the rationale of contrast imaging of plaque vascularization. Methodological limitations and possible future applications are discussed.

Neue Trends in der Ultraschalldiagnostik der Karotisstenose

The B-mode image quality of vessels has markedly increased with the advent of new transducer technologies. Morphological changes of the vessel wall, ulcerations, dissections or wall lesions benefit from non-Doppler dependent flow imaging methods. Two-dimensional imaging of the elasticity of the vessel wall may in future benefit from high speed imaging techniques. The biggest improvement in vessel imaging is probably the prudent use of contrast-enhanced ultrasound by which neovascularization can be visualized. Plaque vascularization is looked upon as an important risk factor in the evaluation of possible vulnerable plaques.

0035: Contrast Enhanced Ultrasound (CEUS) in the Assessment of Carotid Plaque Vascularization. Correlation with the Vessel Density in the Immunohistochemical Study

0035: Contrast Enhanced Ultrasound (CEUS) in the Assessment of Carotid Plaque Vascularization. Correlation with the Vessel Density in the Immunohistochemical Study

Focus on the &amp;#x201C;Unstable&amp;#x201D; Carotid Plaque: Detection of Intraplaque Angiogenesis with Contrast Ultrasound. Present State and Future Perspectives

Over the past 20 years, conventional ultrasonography has identified features of the "unstable" carotid plaque. Histological studies have recognized that plaque inflammation and neoangiogenesis play a pivotal role in the developing of the vulnerable plaque. Hence, the growing interest on the biological activities of atherosclerotic lesions leading to cerebrovascular events. The presence of adventitial vasa vasorum and the occurrence of plaque vascularization have been considered as predictors of unstable lesions in cerebrovascular and/or cardiovascular patients. The advent of ultrasound contrast agents has represented a fundamental step in the up-to-date functional evaluation in several fields with minimally invasive procedures. Contrast specific ultrasound modalities are currently used with excellent results in oncology, in cardiology and in vascular diseases. Contrast carotid ultrasound is an emerging imaging technique, able to depict in vivo new functional information on plaque activity and vascularization that may add further new data on the actual condition and future cerebrovascular risk. Further studies will provide a better clarification of the degree of neo-angiogenesis. A future strategy could be represented by the monitoring of plaque neoangiogenesis in order to detect the possible pharmacological effects on plaque remodeling.

The Antiangiogenic Activity of rPAI-1 23 Inhibits Vasa Vasorum and Growth of Atherosclerotic Plaque

Plaque vascularity has been implicated in its growth and stability. However, there is a paucity of information regarding the origin of plaque vasculature and the role of vasa vasorum in plaque growth. To inhibit growth of vasa vasorum in atherogenic mice and assess its effect on plaque growth, we used a truncated plasminogen activator inhibitor (PAI)-1 protein, rPAI-1(23), that has significant antiangiogenic activity. Female LDLR(-/-)ApoB-48-deficient mice fed Paigen's diet without cholate for 20 weeks received rPAI-1(23) treatment (n=21) for the last 6 weeks. Plaque size and vasa vasorum density were compared to 2 controls: mice fed Paigen's diet and treated with saline for the last 6 weeks (n=16) and mice fed Paigen's diet until the onset of treatment (n=14). The rPAI-1(23) treatment significantly reduced plaque area and plaque cholesterol in the descending aorta and plaque area in the innominate artery. Measurements of reconstructed confocal microscopy images of vasa vasorum demonstrate that rPAI-1(23) treatment decreased vasa vasorum area and length, which was supported by microCT images. Confocal images provide evidence for vascularized plaque in the saline-treated group but not in rPAI-1(23)-treated mice. The increased vessel density in saline-treated mice is attributable, in part, to upregulated fibroblast growth factor-2 expression, which is inhibited by rPAI-1(23). In conclusion, rPAI-1(23) inhibits growth of vasa vasorum, as well as vessels within the adjacent plaque and vessel wall, through inhibition of fibroblast growth factor-2, leading to reduced plaque growth in atherogenic female LDLR(-/-)ApoB-48-deficient mice.

Angiogenesis in Carotid Atherosclerotic Lesions Is Associated with Timing of Ischemic Neurological Events and Presence of Computed Tomographic Cerebral Infarction in the Ipsilateral Cerebral Hemisphere

We studied the association between plaque vascularity, timing of neurological and ocular symptoms, and presence of cerebral infarction in the ipsilateral cerebral hemisphere on preoperative computed tomographic (CT) scan. Consecutive patients undergoing carotid endarterectomy for carotid stenosis were included. All patients underwent preoperative noncontrast cerebral CT. Histological sections were obtained from carotid endarterectomy specimens and stained with an endothelial cell marker (CD34). Microvessel counts were performed in CD34-stained sections and verified through computerized image analysis. Associations between microvessel density in carotid atherosclerotic plaques, preoperative ipsilateral CT evidence of cerebral infarction, and timing of ipsilateral neurological and ocular events were assessed. Seventy-three patients underwent carotid endarterectomy, of whom 17 were symptomatic within 30 days of carotid endarterectomy, 11 were asymptomatic, and a further 45 had a preoperative symptom-free interval of 31-540 days (median = 56). Eighteen patients (24.6%) had CT evidence of cerebral infarction. Significantly higher microvessel counts were observed in patients with CT evidence of cerebral infarction in the appropriate hemisphere compared with patients who did not (p = 0.02). There was an inverse relationship between the microvessel density in atherosclerotic lesions and the timing of ischemic neurological events (odds ratio [OR] = 4.63, 95% confidence interval [CI] 2.95-7.28, p < 0.001). This relationship was independent of patient age (OR = 1.03, 95% CI 0.55-1.99, p = 0.70), sex (OR = 1.18, 95% CI 0.47-2.05, p = 0.56), smoking (OR = 1.07, 95% CI 0.54-2.09, p = 0.84), diabetes (OR = 0.90, 95% CI 0.45-1.79, p = 0.76), and hypercholesterolemia (OR = 0.98, 95% CI 0.68-1.11, p = 0.88). This study confirms the relationship between angiogenesis in carotid atherosclerotic lesions and development and chronology of ipsilateral hemispheric neurological events.